4917391621 has 4 divisors (see below), whose sum is σ = 5037328044. Its totient is φ = 4797455200.

The previous prime is 4917391571. The next prime is 4917391637. The reversal of 4917391621 is 1261937194.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2485521025 + 2431870596 = 49855^2 + 49314^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4917391621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4917391681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59968150 + ... + 59968231.

It is an arithmetic number, because the mean of its divisors is an integer number (1259332011).

Almost surely, 2^4917391621 is an apocalyptic number.

4917391621 is a gapful number since it is divisible by the number (41) formed by its first and last digit.

It is an amenable number.

4917391621 is a deficient number, since it is larger than the sum of its proper divisors (119936423).

4917391621 is a wasteful number, since it uses less digits than its factorization.

4917391621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119936422.

The product of its digits is 81648, while the sum is 43.

The square root of 4917391621 is about 70124.1158304331. The cubic root of 4917391621 is about 1700.5063798299.

The spelling of 4917391621 in words is "four billion, nine hundred seventeen million, three hundred ninety-one thousand, six hundred twenty-one".